The invention relates to a rotary-linear unit, on whose front end there projects the operative drive section of an output drive part able to be driven by means of a rotary drive and a linear drive for both a rotary motion about its longitudinal axis and also for a linear stroke motion in the direction of its longitudinal axis, the rotary drive and the linear drive being arranged in sequence along the longitudinal axis of the output drive part.
In the case of such a known rotary-linear unit the rotary drive is arranged in the part axially between the operative section of the output drive part and the linear drive. The output drive part is designed in the form of a rod and is mounted on a piston, which is reciprocatingly received in the linear drive for fluid power operation. Starting at the piston the output drive part extends through the rotary drive in order to extend at its other end section, which constitutes the operative section, from the rotary drive at the end opposite to the linear drive. The rotary drive furthermore possesses a fluid operated linearly driven piston, which is connected with the output drive part in such a fashion as to prevent relative twist while being to be slid axially thereon. Additionally such piston is connected with the aid of a sliding guide with the surrounding housing. When there is an axial motion of the piston of the rotary drive a rotary movement is imparted to the output drive part. The additional linear stroke movement imposed is rendered possible by actuation of the piston of the linear drive.
Although in the case of such a rotary-linear unit the output drive part is relatively well supported in a direction perpendicular to its longitudinal direction, there is however the disadvantage of a comparatively large overall axial length. Although furthermore there has been a proposal to design the rotary drive in the form of a rack mechanism leading to a reduction in the axial dimensions, in such a case the transverse dimensions are substantially increased, since the housing containing the rack extends at a right angle to the longitudinal axis of the output drive part. In both cases it is consequently necessary to make more space available at the position where the unit is to be mounted.